Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Back action Replacement on 1969 Steinway L

I have a 1969 Steinway L with a noisy teflon back action. I need to replace it. Wondering if the Tokiwa Damper Action Kit Schaff 1028 RT will work, or am I safer ordering the frame and underlevers from Steinway?

Have you ever replaced a Steinway back action?
I have used the Renner kit and the WNG kit with good results.
No experience with Tokiwa kit.
If yours is like the typical SS back action you will find a pivot/leverage issue that if you don't want to redesign it you may be better off with a factory SS kit.
The tray and the levers pivot on two different planes.
there is a PTG Journal article years ago that describes the process.

The Tokiwa kit will work just fine though it is a lot of work to install. The Steinway levers come already installed on the rail so you don't have to lay out and drill the damper tray. Don't assume the geometry of the original back action is correct on this vintage Steinway. It almost always can be improved. If the Steinway has a pitman, its good to replace it with the modern system.

I like to have the damper tray pivot on the same axis as the damper levers. It allows the damper stop rail to be set closer.

I had a customer insist that I replace his worn out one with genuine $teinway and he's been paying a price ever since. If you get the pre-assembled back action from $teinway you will need to pay attention to a couple of things.

Check ALL the pinning on every action center. Check every lead weight for being tight in it's hole. Check your wallet for the extra money it will cost (you already knew this though.)

If you have no experience a pre-assembled OEM will be no worse a design than the original, but it will still require more work than just trading parts. New parts will undoubtedly be dimensionally different than whatever was being made in the teflon era.

The Tokiwa will work as will the WNG or the Renner. All three of those choices give you some opportunity to re-align the action tray pivot with the underlever center and improve functionality. It's an automatic thing with the WNG but the last time I checked, Renner and Tokiwa stick to the original Steinway misalignment unless you are willing to do some extra work to move pinning around.

The newest Tokiwa back action kit for a Steinway from Pacific Piano supply has a provision to locate the lift tray pivot pin concentric with the underlever flange. I prefer the Tokiwa to Renner or NY Steinway. The NY factory action will almost surely not match the spacing of the back of the keys very well. You make up the new action to match the spacing of the key ends.

David Hughes, RPT did a superb article in the PTG Journal 3 or so years ago. It mirrors my installation method with the exception I do not install capstans into the lift tray for damper lift adjustment. I do not care for capstans on dampers. It adds unneeded weight and reduces the stiffness of the lift tray.

Steinway publishes instructions for replacing the back action.

Perfect - thank you for all the replies. I've taken the the damper class at the Steinway factory but this is my first replacement.

Can the old damper wires be re-used, or am I better off bending new wires?

[quote=Ed McMorrow, RPT]The newest Tokiwa back action kit for a Steinway from Pacific Piano supply has a provision to locate the lift tray pivot pin concentric with the underlever flange.

Good to know, Ed

Replacing the wires will add a lot of extra time . Use the originals.

Greetings,
I have used all three mentioned back actions. The only one that didn't have pinning problems, either on installation, or three or four years later, was the Tokiwa. The WNG back actions haven't been in service long enough to compare, but they all seem to be doing exactly what they are supposed to be doing.

The question of factory geometry is interesting, and not clearly answered. By placing the tray pivot behind the flange pivot, there is a need for more unstop clearance, which can be minimized by regulating dampers to the keys with the tray as high as possible. The off set also creates a rocking motion at the damper head, which some pianists find provides better half-pedal control.

Creative dimensions on the back rail cloth and/or key end felt can improve the interaction of arcs between key and under lever. Most post-war factory jobs I have seen have the tray pivots too high. This may be for production margin of error, but the Teflon back actions usually were totally out of sync and deeply dug trenches in the felt were the result. It is usually a mistake to simply replicate what is there.

I think you would do well to mock up the back action on the bench and find what pivot height results in the under lever being slightly above horizontal when the key is at full depression. This is a good starting point, but may require removal of material from the dags. It may also weird out the sostenuto, but that depends on how much room you have to work with under the belly-rail.

Wires can be straightened, but check that the length is sufficient for some of the aftermarket top-posts.
Regards,

Within the last two years I have installed WNG, Renner, Tokiwa, and Steinway back actions. Tokiwa is my favorite, though the adjustability of the WNG parts is nice. Tokiwa has two styles for Steinway. One for the fixed tabs and one for the current dampers. Tokiwa does indeed come predrilled for the pivot to match the flanges, but you could still drill the tray to match the old design.

I made up some adjustable blocks for setting up the tray. They have a screw on the back and the bottom of the blocks so I can adjust the tray front to back and up and down. When I am happy with the geometry, I measure the final dimensions of the adjustable blocks and then make the replacement blocks. Makes life a lot easier.

Greetings,
I would add that Steinways often have the tray mounted non-parallel to the back wall of the action cavity. If this is so, the back edges of the mounting blocks MUST me sawn to mimic the resulting angle, otherwise,the holes which are drilled perpendicular to the blocks will not line up.

It would be possible to drill the holes on a bias and mount the blocks square to the back wall, but it won't take much to be off far enough to create binding in the tray.
Regards,

Thank you, again. I'll use the old wires and heads. I don't have a workshop at the University and I was going to do the back action in the office where the piano resides over the summer, but these alignment issues might be better addressed by moving the piano to my workshop. I like the adjustable block idea, Bill. This is an All Steinway University, and in he past they like to use "Steinway parts" and that will probably be the case here. The labor to lay out and drill the tray will negate the parts savings.

As I said, Steinway has instructions. It is in their CD service manual, Chapter 6 page 24.

Not too long ago I replaced a Steinway back action with all new wires and heads. It was one of the most challenging projects I've taken on.

I'd recommend collaborating with a mentor on this - someone who has been through it several times and is intimately familiar with the pitfalls. We tend to work alone too much in this industry. Working with another tech can be very rewarding for both parties.

It could be the difference between enjoying the project or wanting to push the piano off a cliff.

Thank you, BDB !